Have you ever looked out of a plane window and seen the little flaps on the wings moving up and down? Those flaps, along with the shape of the wings, help create a force called lift. Lift is what lets planes rise up and stay in the sky.
But what exactly is a force? A force is just a push or a pull in a certain direction. For example, if you push a swing, that’ s a force.
Planes use four main forces to fly:
THRUST DRAG WEIGHT LIFT pushes the plane forward( from the engines).
pushes back on the plane, like wind in your face.
pulls the plane down because of gravity.
pushes the plane up.
How Do Planes
Fly?
Thrust
Lift
Weight
Drag
Air is made up of lots of tiny, invisible particles that can push on things. Imagine 2 boxes- 1 is small, filled with many air particles that are moving rapidly in the box. This box has high pressure, and the larger box with few air particles moving slowly has low pressure. Air always tries to move from high pressure to low pressure to balance it out across the whole area.
This means, for both boxes, their air particles eventually will all be evenly spaced, moving at the same speeds
When you picture an airplane wing, you’ d see that the top of the wing is curved, and the bottom is flatter. As the plane moves forward, some air goes above and below the wings. The air on the bottom goes faster, which means it has higher pressure. The air on top moves slower( since the curved wing shape means it takes longer for the air to travel across) so it has lower pressure. Since air wants to move from high to low pressure, the air underneath pushes the wing upward. This upward push is lift. If the lift is stronger than the weight, the plane rises. If it’ s weaker, the plane goes down. If they’ re equal strength, the plane stays level.
Slower, Low Pressure Air
Faster, High Pressure Air
When a plane takes off, the engines create a lot of thrust to push it forward. As it speeds up, more air flows over the wings, and the lift force becomes greater than the plane’ s weight( since the difference in pressure increases the strength of the lift). That’ s when the plane leaves the ground. When landing, the flaps on the wings come down. This makes increases drag and slows down the plane. Since it’ s moving slower, there’ s also less lift, so the weight is greater and the plane starts going down.
Flying is really about balance. Thrust fights drag. Lift fights weight. By adjusting speed, wing shape, and flaps, pilots can control the plane to go up, down, or stay level. So, the next time you’ re on a plane, look at those little flaps. They’ re not just moving randomly— they’ re helping balance the forces that keep you safely flying through the sky!
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